For those that prefer a vertical fore-grip on a defensive carbine, there are a lot of choices out there. From micro-size polymer grips to works of art in aluminum, there's something to fill the role no matter what you're looking for.
In the case of the Wilcox Stubby Para Grip, what you get is a lightweight grip that folds out of the way for storage or transport. It's tough, provides much-needed purchase for the support hand and even contains a watertight storage area for small parts or batteries.
The vertical fore-grip might seem out-of-favor these days with the rise of the angled fore-grip or the hand-stop-type grips, but there's still good reason for its employ. For those that participate in 3-gun competition, it helps steady the rifle during rapid transitions. In a pinch it can be used as a makeshift rest (and there are numerous fore-grips with built-in bipod mounts).